Nuclear Energy: Nationalize the Fukushima Daiichi Atomic Plant

With a comment by scientists Ferenc Dalnoki-Veress and Arjun Makhijani. Japanese translation is here

Only by bringing the nuclear power station into government hands can scientists find out what really happened, say Taira Tomoyuki and Hatoyama Yukio.

Events at the Fukushima Daiichi nuclear plant following the 11 March 2011 earthquake and tsunami are of crucial importance for the future of atomic energy — in Japan and globally. To respond adequately to the accident, we have to know precisely what happened then and what is continuing to happen now.

To establish the facts, all the evidence and counter-evidence for what might have taken place must be gathered and made public. Only then will the world be able to have faith in the containment plan developed by the Tokyo Electric Power Company (TEPCO), or be able to judge how it should be modified.

Exactly how much damage the Fukushima Daiichi nuclear plant sustained as a result of the 11 March earthquake and tsunami remains to be determined.

Particularly important is finding out whether the 'worst-case' scenario occurred: that is, whether self-sustaining nuclear reactions were re-ignited in the core ('re-criticality'), creating more fission products and heat damage; whether the explosions that rocked the plant days after the earthquake were nuclear in origin, releasing radioactive metals from damaged fuel rods; and whether molten fuel has broken through the reactor's base, threatening environmental contamination.

A group of representatives from the Japanese Diet (called the 'B-team' in relation to the government's 'A-team') was formed on 24 March to develop a response plan for the worst-case scenario. Set up by one of us (H.Y., former prime minister) and including us both, the B-team's other members are Fujita Yukihisa (now a senior vice-minister of finance) and Kawauchi Hiroshi (now chairman of the Deliberative Council on Political Ethics). The team's recommendations — to be released in a future report — will be independent from those of Japan's government, the Nuclear and Industrial Safety Agency (NISA) and TEPCO.

Our investigation has already shown that key pieces of evidence remain incomplete. We do not yet know whether the worst-case scenario happened. To find out, we believe that independent scientists must be given access to the nuclear plant, and that the plant should be brought into national ownership.

Re-criticality

If nuclear reactions are ongoing within the core, they will continue to create fission products, and the heat generated is likely to damage the cooling and decontamination systems. Proof that re-criticality has occurred hinges on the detection of certain isotopes. The radionuclide chlorine-38, for example, has a short half-life of about 37 minutes and can be generated only if neutrons are available. Its presence would therefore indicate current nuclear activity.

Reports of such a detection have been mixed. On 26 March, NISA reported that TEPCO had found 38Cl in a water sample drawn two days earlier, after sea water (which includes sodium chloride) had been injected into the basement of unit 1. On 1 April, NISA questioned TEPCO's analysis, and said that radioactive sodium-24 should also have been present in the sample. However, some scientists claim that 38Cl can be detected even if 24Na is not. On 20 April, TEPCO negated its earlier report, asserting that 38Cl was not seen in the sea water, and neither was 24Na. It did not, however, publish the data from its analysis. Through NISA, we obtained and reanalysed TEPCO's data, which were measured with a germanium semiconductor detector. We concluded that 38Cl was indeed present, and at a level close to that initially reported (1.6 million becquerels per millilitre). In our view, NISA's and TEPCO's questioning of this detection were therefore unfounded.

Another indicator is xenon-135, which is made when uranium or plutonium undergoes fission; it has a half-life of 9 hours. On 1 November, TEPCO detected 135Xe in unit 2. But, because the concentration was low, NISA concluded that the nuclide could have been produced by spontaneous fission of the dormant fuel, so was not necessarily caused by continuing nuclear reactions. The evidence for re-criticality is therefore still inconclusive.

Nuclear explosions

Another question that must be answered is what caused the explosions at the site. They were initially reported as being caused by the ignition of hydrogen generated by a high-temperature chemical reaction between the alloy covering the fuel rods and the vapour in the core. But, again, this has not been settled. Other possibilities include a nuclear explosion, or the ignition of other gases.

Knowing whether a nuclear explosion took place is essential for predicting how much radioactivity might have been released, what it would have consisted of and how far it would have spread, as well as the state of the spent-fuel rods stored in a pool in unit 3. Two observations suggest that this is plausible. First, some metals heavier than uranium have been detected tens of kilometres from the plant. Second, the steel frame on top of the unit-3 reactor building is twisted, apparently as a result of melting.

Solutions for the Fukushima nuclear disaster must be based on the worst-case scenario

Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) reported finding heavy metals such as curium-242 up to 3 kilometres from the reactor site and plutonium-238 up to 45 kilometres away. These isotopes are deadly poisons if ingested, causing internal exposure to radiation. Because 242Cm has a short half-life (about 163 days), and because the concentrations of 238Pu around the plant were much higher than usual, MEXT concluded that these radionuclides were not fallout from past nuclear tests in the atmosphere, so must have come from the Fukushima reactor. If so, they suggest that broken spent-fuel rods might be scattered around the site — a considerable hazard.

Such elements are too heavy to have been borne in a plume, like the lighter caesium and iodine, so they must have been blown out with great force. Whether a hydrogen explosion would have been powerful enough to scatter heavy metals that far remains unclear. And a hydrogen explosion should not have generated enough heat to melt steel. Initially, TEPCO claimed that the explosion in unit 3 generated white smoke; on re-examination, the smoke was black, and therefore unlikely to have been caused by a pure hydrogen explosion. So a nuclear explosion is a possibility. Whether other explosive gases were present on the site would be equally important to establish.

Melt down

Similarly unconfirmed is how much of the concrete base of the reactor has been breached by molten fuel. This is important because TEPCO plans to fill in the core with water to absorb the radioactivity while it extracts the fuel. If the concrete below the reactor is cracked, then radioactive materials could leak into the groundwater.

Until recently, the government did not believe that this was the case. In a 7 June report to the International Atomic Energy Agency, it reported that most of the melted fuels are being cooled in the lower portion of the reactor pressure vessel and that little fuel is thought to have leaked out into the preliminary containment vessel.

However, two weeks ago, TEPCO admitted that molten fuel may have eaten through three-quarters of the concrete under unit 1, and damaged the bases of two of the other reactors. But again, caution is required. No one has actually looked at the fuel inside the reactor core. So the extent of the leakage is yet to be established.

Nationalize and intervene

Solutions for the Fukushima nuclear disaster — from how to lock up radioactive contamination for half a century to how to discard the reactor core and the molten fuel — must be based on the worst-case scenario, even if the people most involved remain optimistic that this wasn't the case. Although many facts remain to be established, in our view, two things must be done.

First, the Fukushima Daiichi nuclear power plant must be nationalized so that information can be gathered openly. Even the most troubling facts should be released to the public. Nationalization is inevitable, moreover, because the government is obliged to investigate and provide compensation for the disaster.

As an illustration of how information about the accident is being restricted, our committee struggled to obtain even a manual for the plant when we requested it in August. Initially, TEPCO refused to supply it. When a copy was eventually sent to us, a month later, many passages (including key temperatures and emergency procedures) had been blacked out. TEPCO said that it considered those parts to be its intellectual property and of possible security concern. Only after six months did TEPCO release the full manual to us. It was important that we saw the manual to learn why the company had switched part of the emergency core-cooling system off and on again after the earthquake (and before the tsunami) — to find out when the emergency systems were destroyed.

Second, a special science council should be created to help scientists from various disciplines to work together on the analyses. That should help to overcome the dangerous optimism of some of the engineers who work within the nuclear industry. Through such a council, the technologies needed for decommissioning and decontamination and for construction of a deep geological repository for radioactive waste can be developed, even for a worst-case scenario.

Taira Tomoyuki is a member of the House of Representatives in the Japanese Diet.

Hatoyama Yukio is a member of the House of Representatives in the Japanese Diet. He was prime minister of Japan from 2009 until 2010.

Their report appeared in Nature480, pp. 313–314, 15 December 2011.

Comment on the Comments by Prime Minister Yukio Hatoyama and Representative Tomoyuki Taira

Ferenc Dalnoki-Veress and Arjun Makhijani

Former Prime Minister Hatoyama Yukio and Representative Taira Tomoyuki wrote a bold, courageous and very public comment in the December 15 issue of Nature magazine calling for the immediate nationalization of the Fukushima Daiichi (FD) nuclear power plant. Their biggest frustration is the problem that TEPCO has inflicted on the public since day 1 of this tragedy: a lack of transparency, a lack of being forthcoming about the depth and breadth of the problem. We are dismayed to learn that TEPCO refused to give the reactor manual even to the former Prime Minister of Japan at first, and when it did, it redacted portions.

The article throws some light on what TEPCO might be trying to hide. TEPCO has declared a successful “cold shut down” while the authors quite rightly point out that this claim may be irrelevant given that some of the fuel has reached the concrete floor and may breach it, posing a threat of unremediable contamination of ground water. Now that TEPCO has announced a “cold shutdown”, surely they should be able to access the concrete base and verify its integrity!

The article also indicates that TEPCO and the Japanese nuclear regulator may have misled the public when they stated in April 2011 that a measurement that provided evidence for ‘re-criticality’, that is a restart of a chain reaction for at least a brief spurt, was incorrect. After the former Prime Minister and his team finally got the raw data, they concluded that a re-criticality could not be ruled out – the evidence was inconclusive.

We raised this issue in a paper (available in English and Japanese) by one of us (Dalnoki-Veress), released March 28. There we analyzed the implications of TEPCO’s Chlorine-38 measurement from sea water in the turbine of FD reactor #1. At the time, sea water was used to cool the reactor in the absence of access to regular water. We estimated the neutron flux in the reactor core needed to explain the measured concentration of Chlorine-38 (which is an activation product of non-radioactive Chlorine-37 naturally present in the salt in sea-water). This led to the uncomfortable conclusion that natural spontaneous fission could not explain the measured Chlorine-38 concentration; the possibility of a re-criticality was clear and could not be ignored. It could happen again. Our fear at the time was that a re-criticality could cause workers to be “in considerably greater danger than they already are when trying to contain the situation”. We hoped that TEPCO would take our concerns into consideration and respond to our conclusion by further analysis, especially as many analysts have mentioned the need to measure the concentration of sodium isotopes. After the paper was published, TEPCO claimed the measurement was in error.

The authors of the comment in Nature have taken an independent look at the TEPCO data and found the data to be consistent with the initial March 25th measurement of Chlorine-38. This implies that as we suggested in late March the possibility of re-criticality cannot be ignored. Efforts must also be made to determine why so many official simulations don’t predict a re-criticality. An independent investigation is clearly called for not only to determine if TEPCO covered up the results, but to understand what actually happened for the sake of future safety.

The immense problem of cleanup at the site, which will take decades and cost untold sums of money, the problem of people who have no homes to go back to, the problem of contaminated businesses and schools and farms – none of these problems can be addressed with confidence with TEPCO in charge of FD. In any case, the company does not have the assets to deal with the damage and compensation claims.

We agree and echo the authors call for an independent scientific committee to look at all the data in an objective way devoid of the “dangerous optimism” of those who work within the nuclear industry. Nuclear safety demands that the damage from the earthquake prior to the tsunami and possible damage from the aftershocks be understood. Secrecy is inimical to safety and it is also hostile to democracy. But nationalization must be carried out on condition of complete transparency — including publication of all prior documents and measurements, including raw data. Governments are no strangers to secrecy; nationalization will not help if we go from corporate secrecy to a governmental one.

The stakes are high for Japan and indeed for the world, since despite the disaster at FD nuclear power is expected to expand in Asia and the Middle East. In addition, immediate risks for workers attempting to mitigate the situation need to be quantified and fundamental questions need to be asked about the risks the industry poses for society. Certainly they need to be posed before TEPCO and other Japanese corporations are allowed to sell their nuclear power wares to third countries.

Ferenc Dalnoki-Veress is a Research Scientist at the James Martin Center for Non-Proliferation Studies of the Monterey Institute of International Studies. He is a specialist on nuclear disarmament and on aspects of global proliferation of fissile materials. He holds a PhD in high energy physics from Carleton University, Canada, specializing in ultra-low radioactivity background detectors. He can be contacted here: ferenc.dalnoki@ miis.edu and 831- 647-4638.

Arjun Makhijani is president of the Institute for Energy and Environmental Research (www.ieer.org). He holds a Ph.D. in engineering (specialization: nuclear fusion) from the University of California at Berkeley and has produced many studies on nuclear fuel cycle related issues, including weapons production, testing, and nuclear waste, over the past twenty years. He is the author of Carbon-Free and Nuclear-Free: A Roadmap for U.S. Energy Policy the first analysis of a transition to a U.S. economy based completely on renewable energy, without any use of fossil fuels or nuclear power. He is the principal editor of Nuclear Wastelands and the principal author of Mending the Ozone Hole. He can be contacted here: arjun@ieer.org.